Forced Draught Burners

We service and perform maintenance on forced draught burners. Regular maintenance is crucial to ensure that your forced draught burner is operating at maximum safety and efficiency.

What makes a forced draught burner different from a standard burner device is that the fuel and oxidising agent required to create the necessary combustion reaction do not combine until they enter the burner head, where they are then mixed together. The oxidiser and fuel are both sent to the burner head at high pressure which ensures that the two elements are combined thoroughly and efficiently.

Forced draught burners are capable of controlling the combustion of all gaseous fuels (such as: methane, LPG, town gas) and liquid fuels (diesel oil, heavy oil). There are types of burners that use only one family of fuel (liquid or gaseous) and other types that can use both, these are known as ‘dual fuel’ (aka. double fuel) burners.

Thus, three classes of burner are obtained:

• Burners of gas fuels which use only gas fuels

• Burners of liquid fuels which use only liquid fuels

• Burners of liquid and gas fuels (dual fuel) which use both gas and liquid fuels.

Forced draught burners can also be classified according to the type of construction:

• Monobloc burners

• Separate fired burners or DUALBLOC.

In monobloc burners, the fan and pump are essential components and form a single body within the burner. In DUALBLOC burners, the fan, pump and/or other fundamental parts of the burner are separate from the main body (head). Monobloc burners are those most commonly used in output ranges varying from tens of kWs to several Mw output. For higher outputs, or for special industrial processes, DUALBLOC burners are used.

Depending on output delivery type, forced draught burners can be classified according to the following distinctions:

• Single-stage burners

• Multi-stage burners

• Modulating burners

The future of forced draught burners

Although the ErPD appears to prefer the fully condensing pre-mix burner for the provision of heat and hot water generation for commercial and non-domestic buildings, a need still exists for forced draught burners.

Compared to pre-mix, forced draught burners are compatible with a wider range of applications, and are therefore much more diverse. Indeed, for a number of industrial applications, forced draught burners will always be an essential requirement. With correct matching, forced draught burners can achieve the same efficiency as pre-mix burners, and even more with the addition of technology such as O2 and CO trim.

A lot of the efficiency from forced draught burners is lost in maintaining higher stack temperatures to prevent condensation forming inside a boiler that is not designed to dispose of it. In this situation it is normally possible for the burner to offer a greater turndown ratio than that which the boiler is designed to cope with.

Overall, both types of burner can offer optimum efficiency towards the application that they are designed for, irrespective of heat output. A more significant consideration is to ensure the appliance and its ancillary equipment are designed, specified, installed and commissioned correctly to suit the application.

The need for a wide variety of different burner types still exists and it is the application that will ultimately dictate the type of burner that is required.